Coastal Erosion and Landfill Exposure: Future Impacts of Climate Change
The UK’s historic coastline is a ticking pollution time bomb that is being rapidly accelerated by the impacts of climate change and landfill exposure.
Beneath the surface of our glorious national coast lies a rather dirty history that is being brought to the surface by the impacts of coastal erosion.
As an island nation the UK has the largest coastline in Europe of 17,381km and is surrounded by four water bodies (Atlantic ocean, North Sea, Irish Sea and English Channel). For this reason, 28% of the UK’s coastline is vulnerable to coastal erosion as climate change has accelerated rising sea levels and increasingly hazardous weather.
If this wasn’t enough of a concern, there are approximately 20,000 historical landfills in England and 1,215 of these are located in coastal settings within the tidal flood zone (0.5% annual probability of coastal flooding). Of these, 79 are at risk of erosion by 2025 if not defended. These coastal landfills contain a range of waste types from domestic, commercial and industrial waste, to hazardous and liquid sludge.
Historical coastal landfills are associated with environmentally sensitive areas as they were located on cheap land prone to flooding and took waste from local populated areas. In turn, landfills are close to estuaries, industrial centres and major cities, where there is growing concern that coastal erosion will release harmful contaminants into the environment harming people, local habitat and property prices.
History of landfills
The disposal of solid and hazardous waste in landfills was common practice from the 19th century when there was no regulation. Waste was disposed of in sites with no impermeable lining, no leachate or gas monitoring and limited reporting of waste types. As a result, these landfills rely on natural attenuation through surrounding soils and sediments to disperse and dilute the leachable contaminants and so reduce pollution impact on surface and ground waters. In more recent decades waste disposal permits were introduced in 1974 with the Control of Pollution Act (CoPA) and these now ‘historic’ landfills have closed. Yet, the contaminated material they contain still remains.
Coastal landfills are susceptible to erosion if they are not adequately maintained as rising sea levels and hazardous weather accelerate. The majority of coastal landfills are protected through Shoreline Management Plans (SMP) produced by Local Authorities in conjunction with the Environment Agency. When identifying the most sustainable approach to managing the risks of flooding and coastal erosion, they consider three different epochs: Short-term (0 to 20 years), medium-term (20 to 50 years) and long-term (50 to 100 years). SMPs can involve active defences such as seawalls or more natural defences such as beaches and dunes. The four most commonly used SMP policies are:
1) Hold the line: An aspiration to build or upgrade artificial defences to maintain the current shoreline.
2) Advance the line: New defences are built seaward of existing defences,
3) Managed realignment: Allowing the shoreline to move naturally, but managing the process to direct it in certain areas. This is usually done in low-lying areas, but may occasionally apply to cliffs.
4) No active intervention: “There is no planned investment in defending against flooding or erosion, whether or not an artificial defence has existed previously”.
There are drivers in choosing how to defend an historic landfill. In the UK a key requirement is that the landfill should not breach statutory water quality standards and changes in chemistry would be particularly impactful as approximately 30% of landfills are close to environmentally sensitive estuarine and coastal habitat. As a result the tendency is to choose a ‘hold the line’ approach. But this has consequences as this can accelerate erosion of the surrounding coastline and is expensive. Alternatives, such as relocating the waste is costly and unsustainable where remaining landfill space is at a premium (only 360 million m3 of permitted capacity remains in the context of 6 million tonnes of food waste alone being disposed of landfill per year). The research suggests that managed retreat may be more sustainable.
As always, obtaining funding underpins further actions and a mixture of current and potential future land as well as nuisance, impact on health and ecology all play a role in decision making. We can see this in action with the following case studies.
The principal route to funding is the Flood and Coastal Erosion Risk Management Projects Funding (FCERM), designed to support flood or coastal erosion risk schemes at strategic and implementation levels. This is linked to Grant-in-Aid funding which is designed to encourage wider funding partnerships to contribute to coastal protection schemes.
Whilst most historical landfills are repurposed as recreational sites or used for commercial or industrial activity, around a quarter are now residential. Approximately 6,500 residential properties are located on areas of historical landfills. 4,400 of these are in Portsmouth where new defences are being maintained and emplaced over the next 10 years. In these instances there is an emphasis on ‘holding the line’ to protect the property as well as reduce the release of contamination.
For instance, new ‘hold the line’ defences planned at Porchester Quay on Paulsgrove Lake involve installing a sheet piled wall in front of the landfill with a 1 in 200-year standard of protection. In many circumstances funding can be difficult to secure, however this scheme was made possible because 400 residential and 100 commercial properties are at risk of coastal flooding within this floodplain. Flood risk will rise with 662 residential and 141 commercial properties at risk by the year 2115, increasing the case for funding. In this instance funding has been secured through a combination of Flood and Coastal Erosion Risk Management Grant (FCERM GiA), private developers and the local levy.
In contrast, historical landfill sites at the nearby Cam Bay and Birdwood Grove Tips are part of the eroding coastal fringe that is currently used for recreation. This is not currently managed. During the 1970s these sites received commercial and household waste such as glass, red brick and plastics. They have since begun to erode as plastic debris and household items have been found on the foreshore. Investigations showed the quality of the landfill leachate is generally poor, with high concentrations of metals and organics. These sites are largely undefended, though there are some areas of informal defences: degrading concrete sandbags and old concrete blocks. As the adjacent shoreline has habitat designations as SSSI, SPA, and a Ramsar site, it has both national and international conservation significance. Therefore, these sites need study as the erosion of these landfills could present risks to coastal ecological health as well as local people in order to identify a formal management route and secure funding.
On the north east coast, in Northumberland, landfill sites at Lynemouth beach contain an estimated 30 million tonnes of colliery waste. The Colliery spoil cliffs are now actively eroding resulting in waste material being released onto the beach, including not only spoil but also pipework, oils and other infrastructure. In response to the complaints, the council has allocated £5m towards a waste remediation scheme designed to remove material from targeted areas treated off-site. In the meantime to prevent harm to beach users frequent beach inspections, risk assessments and clean-ups are in operation.
Coastal erosion is exposing the UK’s dirty past in ways that present risks to local habitats and developments. Shoreline Management Plans form the basis of protecting these coastal landfills, however, funding for these schemes can be difficult to secure. Many landfill sites are undeveloped and do not qualify for Flood and Coastal Erosion Risk Management Grant in Aid funding, resulting in coastal defences being ‘patched up’ rather than being actively managed and undergoing major capital works.
Understanding your local environment and the potential impact climate change may have on your property is why Groundsure’s Avista and Homebuyers reports now include our ClimateIndex. We provide our customers with an up-to-date analysis of the risk coastal erosion poses to their property over 1, 5, and 30 years whilst detailing which SMP applies to their local coast. This ensures our customers can make confident decisions with the latest information on how climate change impacts their property.
For more information on ClimateIndex™ contact us on 01273 257 755 or email email@example.com
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Jan 9, 2023